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Forum Index : Microcontroller and PC projects : How can you keep a monitor alive...

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Grogster

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Posted: 04:36am 21 Jan 2026
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I have a test area, with an AOC monitor, that has both VGA and HDMI connectors.
With either one, if there is no video detected after about five seconds on either port, the monitor goes to sleep, and this is a MAJOR pain in my arse.

Pretty much ALL monitors in the world, no matter what brand, do this.

Is there anything you can buy, that could perhaps sit between the monitor and the other things I want to connect to it, that will keep the monitor alive NO MATTER WHAT?

Basically, I don't want the monitor to EVER go to sleep, unless I turn the bloody thing off myself.

The constant powering off into sleep mode, is making it really difficult with some things, to see prompts and startup messages, cos the bloody monitor has gone to sleep......again.

And by the time it wakes up, you've missed messages you are trying to see.

Changing the monitor would be pointless - they ALL do this now.

I'd need something that can keep ALL types of video input alive - HDMI, VGA and DVI too, although, I don't need DVI that much, all my testing is either HDMI or VGA.

Anyone know of anything, cos this is driving me bonkers.  
Edited 2026-01-22 09:07 by Grogster
Smoke makes things work. When the smoke gets out, it stops!
 
Plasmamac

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Joined: 31/01/2019
Location: Germany
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Posted: 05:39am 21 Jan 2026
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For vga you need  a fake sync signal (h or v) to keep the screen on. Vesa dpms standard
For hdmi y need a fake tmds clock shield.
You can use a pico with simple „or logic“ to create it.
Maybe you can fake a signal with the pio and a  pico
Plasma
 
phil99

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Posted: 05:48am 21 Jan 2026
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For VGA it is usually Sync. that keeps it on. My guess is just H-sync will if you can inject pulses into that when none are arriving down the cable.

For HDMI & DVI-D only monitors, no idea but if there is a VGA input as well maybe sync pulses may keep the monitor on but don't know if it will revert to HDMI when that appears.

There may be something in the monitor's setup menu that gives HDMI priority over VGA.
Perhaps even a setting to disable "power saving mode".

I use a cheap TV as a HDMI monitor and it doesn't have a power saving mode at all.
 
Bryan1

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Joined: 22/02/2006
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Posted: 06:33am 21 Jan 2026
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Grogs yesterday arvo I used my old Benq 19" monitor to see if I could get into the bios of these 2 optiplex 9020 computers my employer was throwing away so he gladly gave me two of them Now as these computers have dual display ports and the monitor had hdmi found and old serial cable to use.

Now at first got nothing on the screen so I played around with the switch's on the side of the monitor and a popup came with the option of dvi or D-sub so chose D-sub and the screen came to life.

I did try on the second computer but it wouldn't boot and nothing on the screen so I'm glad one of them is OK

So maybe try those options on the monitor and see if works for you.

Regards Bryan
 
PeteCotton

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Joined: 13/08/2020
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Posted: 06:54am 21 Jan 2026
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I'm not sure if this will work for your monitor - but I've noticed that my HDMI video capture card appears to be recognised by my monitor, even when there is no signal. It is going through a HDMI switch after that - but it might worth trying.


https://www.amazon.ca/dp/B0CLNZ8267?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_32&th=1
 
Volhout
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Joined: 05/03/2018
Location: Netherlands
Posts: 5898
Posted: 02:41pm 21 Jan 2026
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@Grogster,

Maybe you can buy a display panel (not a computer monitor). Most (outdoor) display panels I have seen, when there is no input signal, display diagnostics info. Day after day, until someone comes to fix it (restart the PC).

Volhout
Edited 2026-01-22 00:42 by Volhout
PicomiteVGA PETSCII ROBOTS
 
Grogster

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Posted: 11:08pm 21 Jan 2026
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Thanks for all the replies - that gives me something to go on.
The forum software removed the word "Alive" on the thread title - I don't know why.
I added it back(without quotes), to make the thread title make sense again.
Smoke makes things work. When the smoke gets out, it stops!
 
atmega8

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Joined: 19/11/2013
Location: Germany
Posts: 738
Posted: 03:47am 22 Jan 2026
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Grogster,

use cheap HDMI + Dummy-Plug / EDID-Emulator.
Cheap and reliable.


For example
https://www.amazon.de/FUERAN-1920X1080-Passthrough-Compatible-Thunderbolt-60Hz-1080P/dp/B0FZDHSMHT/ref=asc_df_B0FZDHSMHT?mcid=e66fa63d3b63323ebd0f287e779a7146&th=1&tag=googshopde-21&linkCode=df0&hvadid=768874954440&hvpos=&hvnetw=g&hvrand=12591320525016339509&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9192644&hvtargid=pla-2458650457174&hvocijid=12591320525016339509-B0FZDHSMHT-&hvexpln=0
Edited 2026-01-22 13:58 by atmega8
 
Grogster

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Posted: 04:43am 22 Jan 2026
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Never even knew these things existed!
I will do some research on these things, thanks!  
Smoke makes things work. When the smoke gets out, it stops!
 
JohnS
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Joined: 18/11/2011
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Posted: 08:01am 22 Jan 2026
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I couldn't get that amazon URL to work but is it the same as one of these ?

John
 
atmega8

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Posted: 10:42am 22 Jan 2026
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Passthrough HDMI
 
Grogster

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Posted: 05:47am 19 May 2026
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Just a wee follow-up on this topic - I ended up buying a 10" LCD monitor for in-car use.
They are only a hundred bucks, and has composite, VGA and HDMI inputs.

Importantly, it f-ing STAYS on the input you select, with just a blue screen and a "NO SIGNAL" notice floating around the screen, UNTIL I select another input with the AV button.

WHY the more expensive monitor brands DON'T do this, is beyond me.
The amount of hard-core swearing I do at my AOC monitor when it auto-switches to another input if the video vanishes for more then about 3 seconds, would probably be on par with Kevin Bloody Wilson, or Rodney Rude.

This cheap 10" monitor is bliss.
Select the input you want, and it f-ing stays there - unless I change it.  

$100 LCD monitor thing.....
Smoke makes things work. When the smoke gets out, it stops!
 
Mixtel90

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Posted: 07:00am 19 May 2026
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I wonder if they do it to comply with energy efficiency regulations now? It doesn't matter for small displays where the cower drawn isn't much different between running and standby, but it makes a huge difference on bigger screens. Perhaps auto-standby is a way to meet the rules when the running load might be 80W but the standby only 1W.
Mick

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Preliminary MMBasic docs & my PCB designs
 
vegipete

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Posted: 07:26pm 19 May 2026
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Next it would be cool if we could get a 1024x600 native resolution from our various *Mites. But it is sort of a weird resolution.

What resolution are you displaying it, and how well defined is the resulting image?
Visit Vegipete's *Mite Library for cool programs.
 
matherp
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Posted: 08:59pm 19 May 2026
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  Quote  Next it would be cool if we could get a 1024x600 native resolution from our various *Mites. But it is sort of a weird resolution.

Manual - page 154
 
PhenixRising
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Posted: 10:44pm 19 May 2026
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  Grogster said  Just a wee follow-up on this topic - I ended up buying a 10" LCD monitor for in-car use.
They are only a hundred bucks, and has composite, VGA and HDMI inputs.

This cheap 10" monitor is bliss.


Nice one.
 
Grogster

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Posted: 11:04pm 19 May 2026
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  Mixtel90 said  I wonder if they do it to comply with energy efficiency regulations now? It doesn't matter for small displays where the cower drawn isn't much different between running and standby, but it makes a huge difference on bigger screens. Perhaps auto-standby is a way to meet the rules when the running load might be 80W but the standby only 1W.


You have a point there.
But my main problem was not that the AOC monitor goes to sleep, more that it will switch to the VGA input without asking, if the HDMI is disconnected for more then about three seconds.

And vise-versa.

It's a complete pain in the arse when you need it to stay on the selected input.
Smoke makes things work. When the smoke gets out, it stops!
 
Grogster

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Posted: 11:09pm 19 May 2026
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  vegipete said  What resolution are you displaying it, and how well defined is the resulting image?


1024 x 768 @ 60Hz - A standard VGA resolution.
Image is fine, crisp and clear.

I know that earlier "Car monitor" type screens were a bit crap and they tended to have very low maximum resolutions, but this one seems OK.

I could post a photo if you like.
Smoke makes things work. When the smoke gets out, it stops!
 
PhenixRising
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Posted: 07:00am 20 May 2026
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So it sounds like VGA is the default (?)

Would it work if you used the VGA port, via a HDMI-to-VGA adapter?
 
JohnS
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Posted: 09:32am 20 May 2026
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Or maybe it's not the default but instead it doesn't auto-switch away (or off)?

Luckily I've a small monitor-TV type thing that stays on the selected input, which is just what I want.

John
 
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